Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On 25.04.24 22:30, Adam Ford wrote:
> On Thu, Apr 25, 2024 at 4:19 AM Marek Szyprowski
> wrote:
>>
>> On 12.02.2024 00:09, Adam Ford wrote:
>>> When using video sync pulses, the HFP, HBP, and HSA are divided between
>>> the available lanes if there is more than one lane. For certain
>>> timings and lane configurations, the HFP may not be evenly divisible.
>>> If the HFP is rounded down, it ends up being too small which can cause
>>> some monitors to not sync properly. In these instances, adjust htotal
>>> and hsync to round the HFP up, and recalculate the htotal.
>>>
>>> Tested-by: Frieder Schrempf # Kontron BL
>>> i.MX8MM with HDMI monitor
>>> Signed-off-by: Adam Ford
>>
>> Tested-by: Marek Szyprowski
>
> Thank you very much for testing!
>
>>
>>> ---
>>> V2: No changes
>>>
>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
>>> b/drivers/gpu/drm/bridge/samsung-dsim.c
>>> index 8476650c477c..52939211fe93 100644
>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
>>> @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct
>>> drm_bridge *bridge,
>>> adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
>>> DRM_MODE_FLAG_PVSYNC);
>>> }
>>>
>>> + /*
>>> + * When using video sync pulses, the HFP, HBP, and HSA are divided
>>> between
>>> + * the available lanes if there is more than one lane. For certain
>>> + * timings and lane configurations, the HFP may not be evenly
>>> divisible.
>>> + * If the HFP is rounded down, it ends up being too small which can
>>> cause
>>> + * some monitors to not sync properly. In these instances, adjust
>>> htotal
>>> + * and hsync to round the HFP up, and recalculate the htotal. Through
>>> trial
>>> + * and error, it appears that the HBP and HSA do not appearto need
>>> the same
>>> + * correction that HFP does.
>>> + */
>>> + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes >
>>> 1) {
>
> Frieder & Marek S,
>
> Marek V is proposing we eliminate the check against the flags and do
> it unconditionally. If I send you both a different patch, would you
> be willing to try them on your platforms? I don't want to risk
> breaking a board.
> I used the check above from the NXP downstream kernel, so it felt
> safe, but I am not as familiar with the different DSI modes, so I am
> not sure what the impact would be if this read:
>
> if (dsi->lanes > 1) {
>
> Does anyone else have an opinion on this?
My test only covers hardware with the ADV7535 which sets
MIPI_DSI_MODE_VIDEO_SYNC_PULSE. Doing the test without the check for
this flag won't make any difference in this case and it's therefore not
worth repeating the test.
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On 25.04.2024 22:30, Adam Ford wrote:
> On Thu, Apr 25, 2024 at 4:19 AM Marek Szyprowski
> wrote:
>> On 12.02.2024 00:09, Adam Ford wrote:
>>> When using video sync pulses, the HFP, HBP, and HSA are divided between
>>> the available lanes if there is more than one lane. For certain
>>> timings and lane configurations, the HFP may not be evenly divisible.
>>> If the HFP is rounded down, it ends up being too small which can cause
>>> some monitors to not sync properly. In these instances, adjust htotal
>>> and hsync to round the HFP up, and recalculate the htotal.
>>>
>>> Tested-by: Frieder Schrempf # Kontron BL
>>> i.MX8MM with HDMI monitor
>>> Signed-off-by: Adam Ford
>> Tested-by: Marek Szyprowski
> Thank you very much for testing!
>
>>> ---
>>> V2: No changes
>>>
>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
>>> b/drivers/gpu/drm/bridge/samsung-dsim.c
>>> index 8476650c477c..52939211fe93 100644
>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
>>> @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct
>>> drm_bridge *bridge,
>>>adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
>>> DRM_MODE_FLAG_PVSYNC);
>>>}
>>>
>>> + /*
>>> + * When using video sync pulses, the HFP, HBP, and HSA are divided
>>> between
>>> + * the available lanes if there is more than one lane. For certain
>>> + * timings and lane configurations, the HFP may not be evenly
>>> divisible.
>>> + * If the HFP is rounded down, it ends up being too small which can
>>> cause
>>> + * some monitors to not sync properly. In these instances, adjust
>>> htotal
>>> + * and hsync to round the HFP up, and recalculate the htotal. Through
>>> trial
>>> + * and error, it appears that the HBP and HSA do not appearto need
>>> the same
>>> + * correction that HFP does.
>>> + */
>>> + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes >
>>> 1) {
> Frieder & Marek S,
>
> Marek V is proposing we eliminate the check against the flags and do
> it unconditionally. If I send you both a different patch, would you
> be willing to try them on your platforms? I don't want to risk
> breaking a board.
I'm fine with testing it. I also have some additional spare boards to
replace the broken one, but so far none was bricked by my weird testing
activities.
> I used the check above from the NXP downstream kernel, so it felt
> safe, but I am not as familiar with the different DSI modes, so I am
> not sure what the impact would be if this read:
>
> if (dsi->lanes > 1) {
>
> Does anyone else have an opinion on this?
>>> + int hfp = adjusted_mode->hsync_start -
>>> adjusted_mode->hdisplay;
>>> + int remainder = hfp % dsi->lanes;
>>> +
>>> + if (remainder) {
>>> + adjusted_mode->hsync_start += remainder;
>>> + adjusted_mode->hsync_end += remainder;
>>> + adjusted_mode->htotal += remainder;
>>> + }
>>> + }
>>> +
>>>return 0;
>>>}
Best regards
--
Marek Szyprowski, PhD
Samsung R Institute Poland
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On Thu, Apr 25, 2024 at 4:19 AM Marek Szyprowski
wrote:
>
> On 12.02.2024 00:09, Adam Ford wrote:
> > When using video sync pulses, the HFP, HBP, and HSA are divided between
> > the available lanes if there is more than one lane. For certain
> > timings and lane configurations, the HFP may not be evenly divisible.
> > If the HFP is rounded down, it ends up being too small which can cause
> > some monitors to not sync properly. In these instances, adjust htotal
> > and hsync to round the HFP up, and recalculate the htotal.
> >
> > Tested-by: Frieder Schrempf # Kontron BL
> > i.MX8MM with HDMI monitor
> > Signed-off-by: Adam Ford
>
> Tested-by: Marek Szyprowski
Thank you very much for testing!
>
> > ---
> > V2: No changes
> >
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> > b/drivers/gpu/drm/bridge/samsung-dsim.c
> > index 8476650c477c..52939211fe93 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct
> > drm_bridge *bridge,
> > adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
> > DRM_MODE_FLAG_PVSYNC);
> > }
> >
> > + /*
> > + * When using video sync pulses, the HFP, HBP, and HSA are divided
> > between
> > + * the available lanes if there is more than one lane. For certain
> > + * timings and lane configurations, the HFP may not be evenly
> > divisible.
> > + * If the HFP is rounded down, it ends up being too small which can
> > cause
> > + * some monitors to not sync properly. In these instances, adjust
> > htotal
> > + * and hsync to round the HFP up, and recalculate the htotal. Through
> > trial
> > + * and error, it appears that the HBP and HSA do not appearto need
> > the same
> > + * correction that HFP does.
> > + */
> > + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes >
> > 1) {
Frieder & Marek S,
Marek V is proposing we eliminate the check against the flags and do
it unconditionally. If I send you both a different patch, would you
be willing to try them on your platforms? I don't want to risk
breaking a board.
I used the check above from the NXP downstream kernel, so it felt
safe, but I am not as familiar with the different DSI modes, so I am
not sure what the impact would be if this read:
if (dsi->lanes > 1) {
Does anyone else have an opinion on this?
> > + int hfp = adjusted_mode->hsync_start -
> > adjusted_mode->hdisplay;
> > + int remainder = hfp % dsi->lanes;
> > +
> > + if (remainder) {
> > + adjusted_mode->hsync_start += remainder;
> > + adjusted_mode->hsync_end += remainder;
> > + adjusted_mode->htotal += remainder;
> > + }
> > + }
> > +
> > return 0;
> > }
> >
>
> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R Institute Poland
>
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On 12.02.2024 00:09, Adam Ford wrote:
> When using video sync pulses, the HFP, HBP, and HSA are divided between
> the available lanes if there is more than one lane. For certain
> timings and lane configurations, the HFP may not be evenly divisible.
> If the HFP is rounded down, it ends up being too small which can cause
> some monitors to not sync properly. In these instances, adjust htotal
> and hsync to round the HFP up, and recalculate the htotal.
>
> Tested-by: Frieder Schrempf # Kontron BL
> i.MX8MM with HDMI monitor
> Signed-off-by: Adam Ford
Tested-by: Marek Szyprowski
> ---
> V2: No changes
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 8476650c477c..52939211fe93 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge
> *bridge,
> adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
> DRM_MODE_FLAG_PVSYNC);
> }
>
> + /*
> + * When using video sync pulses, the HFP, HBP, and HSA are divided
> between
> + * the available lanes if there is more than one lane. For certain
> + * timings and lane configurations, the HFP may not be evenly divisible.
> + * If the HFP is rounded down, it ends up being too small which can
> cause
> + * some monitors to not sync properly. In these instances, adjust htotal
> + * and hsync to round the HFP up, and recalculate the htotal. Through
> trial
> + * and error, it appears that the HBP and HSA do not appearto need the
> same
> + * correction that HFP does.
> + */
> + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes > 1)
> {
> + int hfp = adjusted_mode->hsync_start - adjusted_mode->hdisplay;
> + int remainder = hfp % dsi->lanes;
> +
> + if (remainder) {
> + adjusted_mode->hsync_start += remainder;
> + adjusted_mode->hsync_end += remainder;
> + adjusted_mode->htotal += remainder;
> + }
> + }
> +
> return 0;
> }
>
Best regards
--
Marek Szyprowski, PhD
Samsung R Institute Poland
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On 4/22/24 3:04 PM, Adam Ford wrote:
On Mon, Apr 22, 2024 at 8:01 AM Marek Vasut wrote:
On 4/22/24 2:09 PM, Adam Ford wrote:
On Sun, Apr 21, 2024 at 9:36 AM Marek Vasut wrote:
On 2/12/24 12:09 AM, Adam Ford wrote:
When using video sync pulses, the HFP, HBP, and HSA are divided between
the available lanes if there is more than one lane. For certain
timings and lane configurations, the HFP may not be evenly divisible.
If the HFP is rounded down, it ends up being too small which can cause
some monitors to not sync properly. In these instances, adjust htotal
and hsync to round the HFP up, and recalculate the htotal.
Tested-by: Frieder Schrempf # Kontron BL i.MX8MM
with HDMI monitor
Signed-off-by: Adam Ford
---
V2: No changes
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 8476650c477c..52939211fe93 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge
*bridge,
adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
DRM_MODE_FLAG_PVSYNC);
}
+ /*
+ * When using video sync pulses, the HFP, HBP, and HSA are divided between
+ * the available lanes if there is more than one lane. For certain
+ * timings and lane configurations, the HFP may not be evenly divisible.
+ * If the HFP is rounded down, it ends up being too small which can cause
+ * some monitors to not sync properly. In these instances, adjust htotal
+ * and hsync to round the HFP up, and recalculate the htotal. Through
trial
+ * and error, it appears that the HBP and HSA do not appearto need the
same
+ * correction that HFP does.
+ */
+ if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes > 1) {
Does this also apply to mode with sync events (I suspect it does), so
the condition here should likely be if (!...burst mode) , right ?
Thanks for the review!
I was only able to test it with the DSI->ADV6535 bridge, and I'll
admit I don't know a lot about DSI interface since I don't have a copy
of the spec to read.
Are you proposing this should be:
if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) && dsi->lanes > 1) {
I just want to make sure I understand what you're requesting.
Yes, exactly this.
Do you think it should also include checks for
MIPI_DSI_MODE_VIDEO_NO_HFP, MIPI_DSI_MODE_VIDEO_NO_HBP or
MIPI_DSI_MODE_VIDEO_NO_HSA?
It seems like if any of these are set, we should skip this rounding stuff.
Now that you ask this question, shouldn't this actually apply
unconditionally , no matter which mode is in use ?
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On Mon, Apr 22, 2024 at 8:01 AM Marek Vasut wrote:
>
> On 4/22/24 2:09 PM, Adam Ford wrote:
> > On Sun, Apr 21, 2024 at 9:36 AM Marek Vasut wrote:
> >>
> >> On 2/12/24 12:09 AM, Adam Ford wrote:
> >>> When using video sync pulses, the HFP, HBP, and HSA are divided between
> >>> the available lanes if there is more than one lane. For certain
> >>> timings and lane configurations, the HFP may not be evenly divisible.
> >>> If the HFP is rounded down, it ends up being too small which can cause
> >>> some monitors to not sync properly. In these instances, adjust htotal
> >>> and hsync to round the HFP up, and recalculate the htotal.
> >>>
> >>> Tested-by: Frieder Schrempf # Kontron BL
> >>> i.MX8MM with HDMI monitor
> >>> Signed-off-by: Adam Ford
> >>> ---
> >>> V2: No changes
> >>>
> >>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>> b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>> index 8476650c477c..52939211fe93 100644
> >>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>> @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct
> >>> drm_bridge *bridge,
> >>>adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
> >>> DRM_MODE_FLAG_PVSYNC);
> >>>}
> >>>
> >>> + /*
> >>> + * When using video sync pulses, the HFP, HBP, and HSA are divided
> >>> between
> >>> + * the available lanes if there is more than one lane. For certain
> >>> + * timings and lane configurations, the HFP may not be evenly
> >>> divisible.
> >>> + * If the HFP is rounded down, it ends up being too small which can
> >>> cause
> >>> + * some monitors to not sync properly. In these instances, adjust
> >>> htotal
> >>> + * and hsync to round the HFP up, and recalculate the htotal.
> >>> Through trial
> >>> + * and error, it appears that the HBP and HSA do not appearto need
> >>> the same
> >>> + * correction that HFP does.
> >>> + */
> >>> + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes
> >>> > 1) {
> >>
> >> Does this also apply to mode with sync events (I suspect it does), so
> >> the condition here should likely be if (!...burst mode) , right ?
> >
> > Thanks for the review!
> >
> > I was only able to test it with the DSI->ADV6535 bridge, and I'll
> > admit I don't know a lot about DSI interface since I don't have a copy
> > of the spec to read.
> >
> > Are you proposing this should be:
> >
> > if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) && dsi->lanes > 1) {
> >
> > I just want to make sure I understand what you're requesting.
>
> Yes, exactly this.
Do you think it should also include checks for
MIPI_DSI_MODE_VIDEO_NO_HFP, MIPI_DSI_MODE_VIDEO_NO_HBP or
MIPI_DSI_MODE_VIDEO_NO_HSA?
It seems like if any of these are set, we should skip this rounding stuff.
adam
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On 4/22/24 2:09 PM, Adam Ford wrote:
On Sun, Apr 21, 2024 at 9:36 AM Marek Vasut wrote:
On 2/12/24 12:09 AM, Adam Ford wrote:
When using video sync pulses, the HFP, HBP, and HSA are divided between
the available lanes if there is more than one lane. For certain
timings and lane configurations, the HFP may not be evenly divisible.
If the HFP is rounded down, it ends up being too small which can cause
some monitors to not sync properly. In these instances, adjust htotal
and hsync to round the HFP up, and recalculate the htotal.
Tested-by: Frieder Schrempf # Kontron BL i.MX8MM
with HDMI monitor
Signed-off-by: Adam Ford
---
V2: No changes
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 8476650c477c..52939211fe93 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge
*bridge,
adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
DRM_MODE_FLAG_PVSYNC);
}
+ /*
+ * When using video sync pulses, the HFP, HBP, and HSA are divided between
+ * the available lanes if there is more than one lane. For certain
+ * timings and lane configurations, the HFP may not be evenly divisible.
+ * If the HFP is rounded down, it ends up being too small which can cause
+ * some monitors to not sync properly. In these instances, adjust htotal
+ * and hsync to round the HFP up, and recalculate the htotal. Through
trial
+ * and error, it appears that the HBP and HSA do not appearto need the
same
+ * correction that HFP does.
+ */
+ if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes > 1) {
Does this also apply to mode with sync events (I suspect it does), so
the condition here should likely be if (!...burst mode) , right ?
Thanks for the review!
I was only able to test it with the DSI->ADV6535 bridge, and I'll
admit I don't know a lot about DSI interface since I don't have a copy
of the spec to read.
Are you proposing this should be:
if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) && dsi->lanes > 1) {
I just want to make sure I understand what you're requesting.
Yes, exactly this.
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On Sun, Apr 21, 2024 at 9:36 AM Marek Vasut wrote:
>
> On 2/12/24 12:09 AM, Adam Ford wrote:
> > When using video sync pulses, the HFP, HBP, and HSA are divided between
> > the available lanes if there is more than one lane. For certain
> > timings and lane configurations, the HFP may not be evenly divisible.
> > If the HFP is rounded down, it ends up being too small which can cause
> > some monitors to not sync properly. In these instances, adjust htotal
> > and hsync to round the HFP up, and recalculate the htotal.
> >
> > Tested-by: Frieder Schrempf # Kontron BL
> > i.MX8MM with HDMI monitor
> > Signed-off-by: Adam Ford
> > ---
> > V2: No changes
> >
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> > b/drivers/gpu/drm/bridge/samsung-dsim.c
> > index 8476650c477c..52939211fe93 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct
> > drm_bridge *bridge,
> > adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
> > DRM_MODE_FLAG_PVSYNC);
> > }
> >
> > + /*
> > + * When using video sync pulses, the HFP, HBP, and HSA are divided
> > between
> > + * the available lanes if there is more than one lane. For certain
> > + * timings and lane configurations, the HFP may not be evenly
> > divisible.
> > + * If the HFP is rounded down, it ends up being too small which can
> > cause
> > + * some monitors to not sync properly. In these instances, adjust
> > htotal
> > + * and hsync to round the HFP up, and recalculate the htotal. Through
> > trial
> > + * and error, it appears that the HBP and HSA do not appearto need
> > the same
> > + * correction that HFP does.
> > + */
> > + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes >
> > 1) {
>
> Does this also apply to mode with sync events (I suspect it does), so
> the condition here should likely be if (!...burst mode) , right ?
Thanks for the review!
I was only able to test it with the DSI->ADV6535 bridge, and I'll
admit I don't know a lot about DSI interface since I don't have a copy
of the spec to read.
Are you proposing this should be:
if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST) && dsi->lanes > 1) {
I just want to make sure I understand what you're requesting.
thanks
adam
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On 2/12/24 12:09 AM, Adam Ford wrote:
When using video sync pulses, the HFP, HBP, and HSA are divided between
the available lanes if there is more than one lane. For certain
timings and lane configurations, the HFP may not be evenly divisible.
If the HFP is rounded down, it ends up being too small which can cause
some monitors to not sync properly. In these instances, adjust htotal
and hsync to round the HFP up, and recalculate the htotal.
Tested-by: Frieder Schrempf # Kontron BL i.MX8MM
with HDMI monitor
Signed-off-by: Adam Ford
---
V2: No changes
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 8476650c477c..52939211fe93 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge
*bridge,
adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
DRM_MODE_FLAG_PVSYNC);
}
+ /*
+* When using video sync pulses, the HFP, HBP, and HSA are divided
between
+* the available lanes if there is more than one lane. For certain
+* timings and lane configurations, the HFP may not be evenly divisible.
+* If the HFP is rounded down, it ends up being too small which can
cause
+* some monitors to not sync properly. In these instances, adjust htotal
+* and hsync to round the HFP up, and recalculate the htotal. Through
trial
+* and error, it appears that the HBP and HSA do not appearto need the
same
+* correction that HFP does.
+*/
+ if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes > 1)
{
Does this also apply to mode with sync events (I suspect it does), so
the condition here should likely be if (!...burst mode) , right ?
Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
On Sun, Feb 11, 2024 at 5:09 PM Adam Ford wrote:
>
> When using video sync pulses, the HFP, HBP, and HSA are divided between
> the available lanes if there is more than one lane. For certain
> timings and lane configurations, the HFP may not be evenly divisible.
> If the HFP is rounded down, it ends up being too small which can cause
> some monitors to not sync properly. In these instances, adjust htotal
> and hsync to round the HFP up, and recalculate the htotal.
>
Marek V and Marek S,
Would either of you be willing to test that this doesn't break your
applications?
thanks
adam
> Tested-by: Frieder Schrempf # Kontron BL
> i.MX8MM with HDMI monitor
> Signed-off-by: Adam Ford
> ---
> V2: No changes
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> b/drivers/gpu/drm/bridge/samsung-dsim.c
> index 8476650c477c..52939211fe93 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge
> *bridge,
> adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
> DRM_MODE_FLAG_PVSYNC);
> }
>
> + /*
> +* When using video sync pulses, the HFP, HBP, and HSA are divided
> between
> +* the available lanes if there is more than one lane. For certain
> +* timings and lane configurations, the HFP may not be evenly
> divisible.
> +* If the HFP is rounded down, it ends up being too small which can
> cause
> +* some monitors to not sync properly. In these instances, adjust
> htotal
> +* and hsync to round the HFP up, and recalculate the htotal. Through
> trial
> +* and error, it appears that the HBP and HSA do not appearto need
> the same
> +* correction that HFP does.
> +*/
> + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes >
> 1) {
> + int hfp = adjusted_mode->hsync_start -
> adjusted_mode->hdisplay;
> + int remainder = hfp % dsi->lanes;
> +
> + if (remainder) {
> + adjusted_mode->hsync_start += remainder;
> + adjusted_mode->hsync_end += remainder;
> + adjusted_mode->htotal += remainder;
> + }
> + }
> +
> return 0;
> }
>
> --
> 2.43.0
>
[PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding
When using video sync pulses, the HFP, HBP, and HSA are divided between
the available lanes if there is more than one lane. For certain
timings and lane configurations, the HFP may not be evenly divisible.
If the HFP is rounded down, it ends up being too small which can cause
some monitors to not sync properly. In these instances, adjust htotal
and hsync to round the HFP up, and recalculate the htotal.
Tested-by: Frieder Schrempf # Kontron BL i.MX8MM
with HDMI monitor
Signed-off-by: Adam Ford
---
V2: No changes
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
b/drivers/gpu/drm/bridge/samsung-dsim.c
index 8476650c477c..52939211fe93 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge
*bridge,
adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC |
DRM_MODE_FLAG_PVSYNC);
}
+ /*
+* When using video sync pulses, the HFP, HBP, and HSA are divided
between
+* the available lanes if there is more than one lane. For certain
+* timings and lane configurations, the HFP may not be evenly divisible.
+* If the HFP is rounded down, it ends up being too small which can
cause
+* some monitors to not sync properly. In these instances, adjust htotal
+* and hsync to round the HFP up, and recalculate the htotal. Through
trial
+* and error, it appears that the HBP and HSA do not appearto need the
same
+* correction that HFP does.
+*/
+ if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes > 1)
{
+ int hfp = adjusted_mode->hsync_start - adjusted_mode->hdisplay;
+ int remainder = hfp % dsi->lanes;
+
+ if (remainder) {
+ adjusted_mode->hsync_start += remainder;
+ adjusted_mode->hsync_end += remainder;
+ adjusted_mode->htotal += remainder;
+ }
+ }
+
return 0;
}
--
2.43.0
